<!DOCTYPE html>
<html>
<head>
  <title></title>
</head>
<body>
  <style>
    #box {
      width: 200px;
      margin: 10px;
      border: 1px solid black;
      background-color: #eee;
    }

    #top {
      height: 333px;
      background-color: red;
    }

    #middle {
      height: 333px;
      background-color: green;
    }

    #bottom {
      height: 334px;
      background-color: blue;
    }
  </style>
  <div id="box">
    <div id="top">top</div>
    <div id="middle">middle</div>
    <div id="bottom">bottom</div>
  </div>
</body>
</html>
